93631 leans heavily Republican by roughly 34 points: about 33% of voters vote Democratic and 67% Republican.
About 59% of adults in 93631 typically vote, near the U.S. average of about 62%. Among adults in 93631, ~20% vote Democratic, ~39% Republican, and ~41% don't vote. The map below shows estimated turnout by block group.
How 93631 compares
Among zip codes within 15 miles, 93631 leans more Republican than 13 of 14 neighbors.
93631 runs about 54 points more Republican than California as a whole. California leans Democratic overall, while 93631 is one of the few Republican-leaning pockets.
Politics vary noticeably by block within 93631. The east side is the most Republican-leaning (R+56) and the west side is the least Republican-leaning (R+25), a spread of about 31 points.
Why 93631 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 93631, not a ranked or complete list of what matters most.
93631 votes against the grain of California. California leans Democratic overall, while 93631 runs about 54 points more Republican.
Never-married share, developed land, and voter turnout
Places that combine a never-married-heavy adult population and a heavily developed built environment tend to turn out at a lower rate, as 93631, CA does.
Why turnout in 93631 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 93631 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Crowded housing lines up with lower turnout, and about 7% of homes in 93631 have more than one occupant per room, above 93% of zip codes. Learn more about the findings and methodology on the political spectrum map.
Nearby Zip Codes
Zip Codes with Similar Populations
Sources and methodology
Precinct-level voting records used to fit the model come from California Secretary of State, Elections, distributed by the Voting and Election Science Team. Demographic inputs come from the U.S. Census Bureau (ACS 5-year estimates and the 2020 Decennial Census). Health and environmental inputs come from the CDC (PLACES and the Environmental Justice Index). Land cover comes from the USGS and EPA. Election-day and lead-up weather come from PRISM 4km daily grids and the NOAA Global Historical Climatology Network. Mail-voting and election-administration patterns come from the MIT Election Lab's Survey of the Performance of American Elections. Block-group crime detail comes from CrimeGrade. Internet data and modeling support provided by ISPreports.org.
Modeling and analysis by the BestNeighborhood data science team. Full methodology and findings: political spectrum map.
Methodology reviewed by the BestNeighborhood data team. Last updated May 2026.